ES2324324B9 - SYSTEM FOR AUTOMATIC SELECTIVE SEPARATION OF CITRUS AFFECTED BY PODREDUMBRE - Google Patents

Description

DESCRIPTION

System for automatic selective separation of citrus fruits affected by rot.

Object of the invention

The present invention relates to a system for the automatic selective separation of citrus fruits affected by rot, which provides essential characteristics of novelty and remarkable advantages with respect to the means known and used for the same purposes in the current state of the art.

More particularly, the invention proposes the development of a highly effective system for the identification of the pieces of citrus fruits affected by rotting problems, and their automatic withdrawal from a product classification line prior to the packaging of the citrus fruit, for which purpose the system incorporates a unit for emission of ultraviolet light, closed to the exterior, constitutive of the unit of vision in which UV light is projected onto the citrus pieces that pass through it on a conveyor, and the state of citrus fruits is determined by virtue of of the nature of the fluorescence observed on them and captured by a camera or image acquisition system, after being filtered. An encoder controls the position of the unwanted parts for automatic separation when they reach the ejection unit located next to said vision unit.

The field of application of the invention is comprised within the industrial sector dedicated to the construction and installation of automatic classification and recognition devices, in particular those intended for the fruit and vegetable sector.

BACKGROUND AND SUMMARY OF THE INVENTION

Experts in the field are aware that the cultivation of citrus fruits is the main national fruit sector. Half of the citrus fruits produced in Spain are destined for export, which is why Spanish citrus fruits occupy a very important place in the context of the producing countries. However, the low production costs of the non-European countries of the Mediterranean area allow their citrus fruit to compete with the market advantage over our productions. If we add to this the progressive opening of European Union markets to these countries, the only alternatives that seem possible to maintain market share are to offer a higher quality product than the competing countries, together with cheaper prices. production costs.

The quality of the fruit is determined by aspects such as presentation, appearance, uniformity, maturity and freshness, all essential components of the purchase decision. The quality of the fruits can be affected by various causes, resulting in morphological and physiological defects that devalue the product. Among the most worrying causes are those that cause defects in the fruit during, or after, the preparation for the market, and that are manifested in the places of sale. The mechanical damages or injuries that take place during the handling of the product, are the gateway for a multitude of pathogens that cause decay, such as the fungi of the genera Botrytis, Rhizopus, Alternaria, Geotrichum, but above all the fungi Penicilium digitatum ( green rot) and Penicilium italicum (blue rot), which cause the most post-harvest infections.

The losses by rottenness are of the order of 3-5% of all the fruits handled in the power stations, arriving to be in the years of abnormal climatology, of the order of 7-12%. To reduce these losses, several triads are made in the processing plant of the fruit, according to criteria such as skin defects, presence of insects, hail damage, deformed fruits, etc. However, this operation is not always effective, due to the possibility that, at the time of tría, the damage caused by the rot is not yet visible externally. Under these conditions, the fungus will develop during storage and transport, spreading the infection throughout the game and causing high economic losses. A quick detection of the infection will be especially important to maintain the quality of the product and avoid economic losses to be able to compete in better conditions in the market.

It is now known in the state of the art to use ultraviolet light to detect infection in the fruit before it develops externally. The known method is essentially based on the fact that, when the infection produced by the fungus evolves, the chemical composition of the fruit tissues is altered, spilling the essential oils contained in the glands of the skin; the illumination of these tissues with UV light reveals their fluorescence, making visible damage that is still latent.

The UV rays constitute the band of the electromagnetic spectrum comprised between 100 - 400 nm, bordering the X rays and with the visible strip. The light is generally divided into three bands with the following wavelengths: UV-C, 100-280 nm; UV-B, 280-315 nm; UV-A, 315-400 nm.

The tria operation taking advantage of the UV light is done manually in special inspection cameras if they are in the processing line, and are usually known as "discos". These cameras consist of dark cabins, of small dimensions, illuminated only with ultraviolet light tubes; These tubes emit a wavelength that corresponds to the UV-A and / or UV-B band. The fruit that develops a fluorescence when passing through the cabin, indicates that the infection is latent, and will be eliminated immediately from the line. Fruits pass over of rollers that rotate and rotate the fruits so that the entire surface of the fruit can be appreciated substantially.

However, the use of UV light in this inspection mode poses some drawbacks. In fact, UV radiation is, among non-ionizing radiation, the one with the highest energy content. This relatively high energy content makes them capable of reacting chemically with matter, producing the so-called photochemical reactions. The biological effects of Uv rays mainly affect the skin, causing more erythema, loss of elasticity and delayed melanogenesis. This type of radiation can also cause ophthalmic diseases such as keratitis, conjunctivitis and cataracts. For these reasons, Uv lamps are considered risk Group I by the Lighting Engineering Society (ANSI / IESNA RP-27.3-96).

Practical recommendations have been established for the safe photobiological use of UV light lamps. These recommendations are based on tolerable radiation limits. Thus, for lamps that emit radiation with wavelengths between 320 and 400 nm, the energy flow must not exceed 1 mW / cm2 and the exposure time must be limited, to a greater extent the smaller the distance to the emitter source. Following these recommendations, the operators working in these inspection booths are taking turns not to stay in the booths for more than an hour. Another recommendation is the use of protective goggles and gloves that absorb the UV radiation received, reducing operator exposure to non-hazardous levels (RD-773/1997 and RD-1002/2002). To control these aspects radiation measurements and specific and periodic medical examinations will be carried out.

The manual selection work in these conditions is tedious and repetitive for the operators. Additionally, this labor represents an important cost for the company.

For all these reasons, the analysis techniques have been evolving in recent years, with a view to achieving fruit classification and rejection systems that reduce the high personnel costs directly related to this process. In this sense, the automation of these tasks will improve the quality of work of these operators, to be performed automatically, limiting the task of the operator to monitor the proper functioning of the system, from the outside, through control monitors.

Currently, there is no knowledge of the existence in the market of an automatic system that allows the detection of fruit rot by taking advantage of the fluorescence of the essential oils when applying UV light, despite the intense investigations that are being carried out in relation to with this type of systems.

The present invention belongs to the sector of the systems in charge of the detection of pieces of fruit, especially citrus, which present some degree of rot, and has been developed with the aim of providing effective solutions to the problems existing in the facilities of the current state of the technique. This objective has been fully achieved through the system that will be described in the following, whose main characteristics are compiled in the characterizing portion of appended claim 1. The dependent claims define the details and particularizations of the system of the invention.

In essence, the system of the invention is intended for the physical separation of fruits that have some type of rot that go through a line of treatment and calibration, by automatic expulsion of the affected fruits, and therefore performs automatically the same task as So far it is being carried out manually.

The principle of operation of the system is based on the use of ultraviolet light, more specifically light from the UV-A and / or UV-B band, to detect the rot that may be developing in citrus fruits, in the same way as used in the manual tria. For this, the system uses the observed characteristic that the essential oils that are released during the development of the rot, react when UV light hits them, emitting a fluorescence. This fluorescence is a radiation of very low intensity, and with a very important component of wavelengths centered in a band of the visible spectrum. This fluorescence is what is identified in the images captured by a camera or image acquisition system, to determine if the fruit is affected by some type of rot.

To achieve this objective, a system has been designed which, in its preferred embodiment, comprises a first unit that acts as an artificial vision organ, in which the fruit that is passing on a conveyor means is illuminated with ultraviolet light, so that in case any rot on one or more specific pieces is detected, the fluorescence emitted by them will be captured by the artificial vision system. This situation is detected by the identification and control organ, preferably a computer, from which an order is sent to an ejection assembly incorporated in a corresponding unit located after the artificial vision unit, so that the piece (or pieces) of citrus fruit identified as affected by rot, are expelled from the conveyor when they reach the corresponding position. The exact position of the piece of fruit that must be expelled is determined with the help of a conventional encoder.

In this way, simple but highly effective, the system identifies the piece of fruit affected by rot and automatically ejects it from the conveyor medium without the need for human intervention.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features and advantages of the invention will be more clearly apparent from the detailed description that follows of a preferred embodiment, given solely by way of illustrative and non-limiting example, with reference to the accompanying drawings. , in which:

Figure 1 (single figure) represents a schematic diagram of the whole of the system proposed by the invention.

Description of a preferred embodiment

As mentioned above, the detailed description of the preferred embodiment of the invention is going to be carried out in the following with the help of the drawing appearing in the single Figure of the drawings, in the that a schematic representation of the system of the invention is shown, with the help of numerical references to designate the parts that make up said system. In this sense, if the graphic representation is observed, it can be seen that the set comprises several differentiated sections, each of which has been included to fulfill a specific mission, and among which is distinguished:

- a conveyor 1 extended between two end rollers, which is moved in a direction of advancement of the fruit which, in the example shown, corresponds to the direction of the arrow F;

- a first constitutive unit of the artificial vision organ, designated in general with 3, intended both for the illumination of the citrus fruit and for the capture of images in relation to the possible fluorescences shown by the defective fruit pieces;

- an ejection unit, designated with the reference number 4, and located downstream of the first unit 3, in which means have been incorporated to eject from the conveyor 1 the pieces of fruit identified as affected by rotting;

- an encoder device 5, intended to accurately determine the position of the pieces of fruit affected by rot and that must be ejected from the conveyor when passing through the ejection unit 4, and

- a control unit 6, preferably consisting of a PC-type computer, and equipped with a specific application software designed in accordance with the various functions of the system.

The conveyor device 1, represented only schematically, can be chosen from a plurality of conveyors known in the state of the art, always being able to provide a rotation of the pieces of citrus sufficient to determine those that as explained before, they may be affected by rot problems. In a preferred form of implementation of the system of the invention corresponding to the representation shown in the drawing, the conveyor consists of a transport and rotation element of the fruit of the type incorporating lever and lever expellers, manufactured and marketed by the firm MAF RODA. The conveyor assembly essentially consists of conveyor chains supported on guides, to whose chains are coupled cylinders coated with rubber, of biconical form, known as "biconos", capable of freely rotating. Due to the shape of the biconos and the fruit, it is possible to arrange all the fruits aligned, one after the other. Before reaching the chamber of the first unit 1, said bicones are rotated on their axis so that the fruits are singled out, and each gap between bicones is occupied only by one piece of fruit.

In a variant embodiment of the conveyor, the rotating biconos affect only the part of the path corresponding to the artificial vision unit, constituting in itself a conveyor portion independent of the rest, the operation of all the conveyor sections being duly synchronized with In order to allow a safe and accurate identification of any defective piece of fruit.

The type of conveyor mentioned above in relation to the embodiment of the invention is only illustrative since it can be substituted by other equally effective versions. Thus, a transport system is known in which the ejection of the pieces of fruit located between the biconos, is carried out by means of a blowing of air under pressure instead of using mechanical levers as described above. In this case, the system includes a solenoid valve controlled by an electronic device, so that when the piece of fruit affected by rotting faces the position of the solenoid valve, the electronic device determines the opening of the latter for the application of a jet. of pressurized air that drives the exit of the piece of fruit from the main conveyor to its collection by another secondary conveyor.

In another embodiment, the transport assembly may consist of one known as a "hands" conveyor, in which there is a previous section in which the rotation of the fruit is carried out, passing then to the mentioned conveyor by hands, where Some pieces in the form of hands, positioned horizontally upwards, are responsible for carrying the pieces of fruit (one piece for each hand) towards the end of the path where they are activated by means of an electromagnet to rotate and invert the position (horizontal towards below) and drop the fruit, then return to the horizontal position upwards so that they are again operational when they reach the beginning of the route.

Also, as an alternative conveyor assembly to those mentioned above and with specific application to the present invention, one could choose what is known as a "cups" conveyor, similar in development to the previous one, in which there are supports for fruit that take the form of "cup." The rotation of the cups in the corresponding position is done by activating a lever that releases the rear part of the cup and allows it to swing backwards due to the weight.

Continuing with the description of the system that appears schematically in the drawing, the artificial vision unit is seen, which has been referenced with 3, and which provides an enclosure whose interior space is illuminated by one or more groups of fluorescent tubes 3a, which emit light from the UV-A and / or UV-B band, and inside the enclosure is also installed a camera 7 or system of capturing images of the upper part of the fruit that dragged by the conveyor 1, passes through the inside of the unit. The images captured by the camera are sent to the control body 6 through an image acquisition card (not shown), for processing with the incorporated software programs. The biconos of the conveyor are rotated when they pass inside the unit 3, so that the images of the fruits can be captured from the different surface portions of the same. According to the invention, several images of each of the fruits are taken to compose the software of the entire surface of each piece of fruit.

The compartment in which the lighting groups 3a are installed, is completely closed in order to avoid the negative influence of the ambient light on the detection of the rot. This is due to the fact that the fluorescence created by the effect of rot on the citrus skin emits in the fringe of the visible spectrum, from which it appears that any external disturbance would be a source of noise during the measurement of the fluorescence.

As stated above, the appropriate UV light source to be able to excite the fluorescence of rotors is that emitted in a wide band of the ultraviolet, specifically in a range of between 320 nm and 400 nm.

As for the camera 7 or image capture system, the use of a camera type based on CMOS technology is preferred, although this is not necessary for the capture of the images. In principle, the camera 7 captures images in the band of visible light, to which an optical filter has been fitted that allows the band of radiation to pass in which the fluorescence of the effect of the rot is observed.

The connection between the camera and the control organ (ie the computer 6) is made through a cable and a digital card (not shown), said card being designed and developed specifically to control from the computer 6, the capture and acquisition of the images captured by the aforementioned camera 7.

Continuing in the forward direction of the conveyor 1, the fruits reach the position of the ejection unit 4. This unit 4 has the mission of physically extracting from the conveyor the pieces of fruit that have been detected as affected by rotting. The assembly incorporates an electronic device 4a for interaction with the control computer 6, as well as an electromagnet connected to said electronic device 4a, so that when activated, it rotates a lever (not visible in the Figure). Each piece of fruit located between adjacent biconos, directly supports an ejector element that when passing over the electromagnet when the latter is activated, rises thereby expelling the aforementioned piece of fruit. Therefore, for the ejection of a piece of fruit, a sequence consisting of the following steps is produced:

- identification by the computer 6 of a piece with rottenness;

- calculation by said computer 6 of the moment in which this piece with rot will reach the position of the electromagnet incorporated in the ejection unit 4;

- sending an appropriate signal from the control computer 6 to the electronic device 4a for activating the electromagnet of the ejection unit 4, a moment before the fruit piece at said ejection position.

As usual, a second conveyor (not shown) is responsible for collecting the fruit ejected and with ducirlas to a place of reception and / or storage.

As mentioned above, the system includes the incorporation of an encoder device 5 associated with the conveyor 1. This allows, in an efficient and safe way, to identify the piece of fruit that when passing through the interior of the compartment of the unit 3 of artificial vision, it has been proven that it is affected by rot. The control is carried out by the computer 6, to which said encoder 5 is preferably connected by means of a serial port. The pulses sent from the encoder to the control computer 6 are of a frequency proportional to the speed of the conveyor 1, so that when the number of pulses sent in correspondence with the advance equivalent to the distance of a bicone is known, the software installed in the control organ 6 allows to know precisely the position of each piece of fruit at all times.

Finally, as defined above, the control unit 6 comprises a computer connected to the different organs of the system. Said computer 6 integrates the appropriate software for the processing of the different information and the sending of the corresponding signals to the organs of interest, from the images captured by the camera 7 and received through the corresponding image acquisition card, until the activation at the right time of the necessary means for the expulsion of one or more pieces of fruit affected by rot and the replacement of the system to its normal operating status. It will be understood that, from the principles set forth in the foregoing description, an expert in the field will be able to carry out the adaptation of the system for the control of several cameras 7 by means of a single computer 6, with the corresponding adaptation of the software, so that you can work simultaneously with several production lines.

It is not considered necessary to broaden the content of this description so that a person skilled in the art can understand its scope and the advantages derived from the invention, as well as develop and carry out the object of the invention. In any case, since the system has been described in relation to a preferred embodiment of the same, the practical implementation may be subject to variations of detail, which may affect the types and characteristics of the bodies that comprise it, without deviating hence the scope of the invention defined by the content of the appended claims.

Claims (10)

(Canceled claim) System according to claim 1, characterized in that said artificial vision unit (3) consists of a compartment closed to the outside, through which the conveyor (1) runs, comprising groups (3a) of emission of UV-A light and UV-B projected on the fruits, and a camera (7) for capturing the fluorescences emitted by the fruits as a result of the UV-A and UV-B light projected onto them, said chamber (7) being equipped with an image acquisition card for sending the images captured by said camera (7) to the general control organ (6). System according to claim 1, characterized in that the unit (4) for automatically ejecting the pieces of fruit in which rot has been detected comprises an electronic circuit (4a) controlled from the general control element (6), said electrical circuit (4a) provided for activating the ejector elements associated with the conveyor (1). System according to claim 1, characterized in that the organ (5) for controlling the position of each piece of fruit is an encoder connected to the general control element (6). System according to the preceding claims, characterized in that the general control element (6) is a computer, preferably of the PC type, equipped with a specific application software adapted to the requirements of the system. 6. System according to claim 2, characterized in that the fluorescence emitted by the fruits by illumination with the groups (3a) of light UV-A and UV-B inside the unit (3) of artificial vision, belong mainly to the band of the visible spectrum corresponding to the colors green and yellow, for which purpose, the camera (7) for capturing images has been equipped with a filter that allows the passage mainly of light corresponding to this color band. System according to claim 3, characterized in that the ejector assembly of the pieces of fruit affected by controlled rotting from the general control element (6) consists, in one embodiment, of an electromagnet actuating a lever situated between biconos of the means conveyor and on which the piece of fruit rests, at the moment in which the defective piece of fruit reaches the ejection position, to physically cause the automatic expulsion of the latter towards a second conveyor for collecting the ejected fruits. System according to claim 3, characterized in that in an alternative embodiment the conveyor (1) associated with the system is of the type of biconos and cylinders, in which the ejector means included in the conveyor (1) consist of a solenoid valve that projects a jet of air under pressure for a predetermined time on the defective part, when it reaches the ejection position. System according to claim 3, characterized in that the conveyor (1) is of the "hands" type, in which support pieces in the form of a hand, positioned horizontally upwards, transport the respective pieces of fruit during the journey to the position in which they must be discharged by reversing the "hands" for their downward positioning, with the consequent drop of the fruit. The system according to claim 3, characterized in that the conveyor (1) is of the type known as a "cup" carrier, in which the pieces of fruit are supported and transported by conveyor elements configured as "cups", and capable of tilting backwards and dropping the respective pieces of fruit when said support elements reach a predetermined position and the release of a lever that frees the rear part to swing due to the effect of the weight in that sense occurs.